The protection of buried assets, such as fiber optic cables, from damage is of paramount concern to the telecommunications company that owns the cables. The primary cause of damage is nearby construction activity unrelated to the cable and its maintenance. This may include digging or excavation for new building construction, boring, maintenance or installation activities by contractors for other utilities, etc.
The National “Call Before You Dig” program is an important aspect in the protection process. This protection process starts with a contractor calling in to the National “Call Before You Dig” call center to report the need to dig at a location. Then the National “Call Before You Dig” call center records the information from the caller. The National “Call Before You Dig” center sends all recorded dig request activity tickets or alerts to all subscribing underground utility providers. Because of the large number of calls received by the center, a national utility such as a telecommunications company may handle several million “dig tickets” or dig requests per year. Each ticket indicates a potentially damaging dig activity, which may be near a cable asset.
Due to this immense ticket volume, most utility companies screen at least a portion of these tickets via automatic means. Each “dig ticket” contains information used to determine a longitude/latitude location for the dig activity, and this location is matched against locations of existing cable assets held within a GIS (geographic information system) application.
This process is known as automatic screening or “auto-screening” and is inherently unreliable. This process may produce two types of errors. A Type I error occurs when a ticket is incorrectly deemed “involved” when that ticket is not dangerously close to a fiber cable location. As used herein, a ticket is deemed “involved” if it is identified as a risk to cable assets. A dig activity at this location would not result in cable damage, but the incorrect suspicion of potential damage does result in additional labor costs from following up on a misclassified ticket and the unnecessary field inspection to keep an already safe cable site safe. A Type II error occurs when a ticket that should be flagged as a problem (“involved”) is instead classified as not a problem. A Type II error is also known as a false negative. This incorrect assignment of “Not Involved” is also called a “screening defect” and generates risk of cable damage from not monitoring a dig activity that is too close to a fiber cable.
It has been found that the reliability of screening dig tickets varies with the geographic location of the ticket. In other words, there is a significant degree of geographic correlation to screening unreliability. The correlation is believed to be based on several factors. Street-level databases are less accurate in some areas so coordinates derived from addresses in those areas may be less accurate. Labels and markings may be inconsistent from one particular local to the next. For example, states and counties may use different nomenclature schemes. The regional Call Centers themselves may introduce errors, so that certain Call Centers may be less reliable than others at accurately capturing ticket location data.
The current procedure for screening dig activity tickets introduces errors that add cost to the overall process. This invention overcomes these issues and provides an automated screening process that takes dig locations from ticket requests and correlates them to known cable locations to determine which ticket dig locations are too close to buried fiber cable. This is done using a method that balances the risk of extra labor charges due to a Type I error with the risk of costs associated with a cable cut due to a Type II error.